Kuryakyn ISO Contoured Throttle Boss (Standard) (Black) Some things just get better over time, like Kuryakyn's new Contoured ISO-Throttle Boss! Updated styling combined with a larger surface area and pad provide even more comfort than the original design while still easing hand and forearm fatigue. The addition of a throttle boss can make the difference between a quick trip and a cross country adventure. They're simple to install and are easily adjustable to suit your needs. Notes: Right side ISO-Grip ONLY. Will NOT fit ISO-Grips for use with GL1800 O.E.M.